参考：http://www.csharpcity.com/2011/ifelse-statements-in-mvc3-with-razor/
简单的可以：
@if(2<1)
{
<p>1</p>
}
else
{
<p>2</p>
}
对比MVC2怎么转换：
In ASP.NET MVC2, if we wanted to write some conditional view code (such as displaying a link if a user is logged in), we could do it like so:
<% if (User.Identity.IsAuthenticated) { %>
<%= "Your XYZ is " + ... %>
<% } else { %>
<%= "[not logged in]" %>
<% } %>
How do we “translate” this into a Razor-style if-statement? Very simply:
@if (User.Identity.IsAuthenticated) {
Your XYZ is ...
} else {
[not logged in]
}
What’s cool about this is a complete lack of <% and %>! This is precisely what Scott Guthrie mentioned in his introduction to MVC3 that Razor enables a very fluid coding flow. You don’t need to stop and think about where to write angle brackets; you just write code, write presentation logic, and it works!